Rotary molecular vacuum still



Nov, 30, 1954 .1. sHAvEl., JR., r-:rAL

ROTARY MOLECULAR VACUUM STILL Filed Sept. 25, 1951 United States Patent1O RQTARY MOLECULAR VACUUM STILL John Shavel, Jr., and Harold E. Zaugg,Waukegan, lll., assgnors -to Abbott Laboratories, North Chicago, Ill., acorporation of Illinois Application September 25, 1951 Serial No.248,194

4 Claims. (Cl. 202-.205)

This invention relates to improvements in vacuum distillation apparatus,and more particularly to a rotary, molecular still.

Included among the objects and advantages of the present invention is ahorizontal still capable of operating under either total reflux or adistilling cycle. The still, furthermore, provides an unobstructed,short-path vapor ilow from the evaporating surface tothe condenser. Themolecular still also provides a film evaporating surface thereby greatlyincreasing vaporizing capacity per unit volume of distilland.

The following description of the preferred embodiment of the inventionis to be understood as an illustration and not a limitation thereof.

In the accompanying drawings:

Fig. 1 is a partial vertical section of an improved molecular stillembodying the features of the invention; Fig. 2 is a vertical section atright ang-les to Fig. 1, along line 2 2; and, Fig. 3 is a detailedsection of a portion of the embodiment of Fig. 1 taken along line 3 3.

Referring to the drawing, a right cylinder 10 of glass construction,having an open end 12 of full diameter and a partial end Wall 14,provides the outer shell or casing of the molecular still. The casinghas an evacuation port 16 adjacent the open end, and a ball joint 18extending outwardly from the partial end Wall. The full diameter openingis closed by a bearing casing 20, which is imperforate, completelysealing the open end of the cylinder. A vaporizing chamber 22 is axiallydisposed inside the cas-ing. The chamber is a right cylinder of glasshaving an end wall 24 and a projecting shaft 26 therefrom. In the formillustrated in the drawing the right cylinder 10 has a length of about270 mm. and an internal diameter of about 80 mm. and the vaporizingchamber 22 has a length of about 155 mm. and an outside diameter ofabout 70 mm; The open end of the vaporizing chamber has a partial endwall 28 turned inwardly forming a distilland barrier. A double-ballbearing 30 is mounted in the bearing casing, and a drive shaft 32extends through the bearing. A chuck 34 terminates one end of the shaftand a bar magnet 33 terminates the other end of the shaft. Theprojecting shaft on the vaporizing chamber is securely held by thechuck. T-he double-ball bearing permits free rotation. A straight tubecondenser 40 extends through the ball joint and the partial wall of thevaporizing chamber. The half ball joint 19 on the condenser completesthe seal of the end of the cylinder. A receiver 42 communicates with theouter end of the condenser through the passage 44. The condenser issupplied with connections 46 for cool-ing medium.

The vaporizing chamber is rotated by a magnetic drive. The magneticdrive comprises magnet 33 attached to the drive shaft inside the bearingcasing. The drive magnet 35 is connected to the shaft of a variablespeed motor 37. As the drive magnet 35 rotates, the magnet 33 follows,rotating the vaporizing chamber.

In operation the vaporizing chamber is attached to the chuck andinserted into the cylinder, which is held in substantially horizontalposition. The connection between the bearing casing and the still casingis sealed by stopcock grease or a gasket. The condenser is placed insidethe vaporizing chamber and rotated slightly to securely seat the balljoint. The condenser is connected to the cooling medium supply, and thedistillate receiver is put in place. The condenser is moved to aposition so ice that the inner end Lis slightly below horizontal, whichis the total redux position. The ball joint permits sutilcient movementof the condenser for various distilling operations. During distillationthe still should be substantially horizontal, so that the distilland isvevenly spread in bottom of vaporizing chamber. The vaporizing Vchamberis rotated at the desired speed by controlling lthe drive motor. As thechamber is rotated, the dis- .tilland -wets the chamber wall, and .athin tlm adheres to the Wall. The film substantially coats the 'entirewall, yexposing a large surface area for evaporation.

In the embodiment of :the invention described, vaporizing heat issupplied lby .an infrared lamp 48, but any means of radiant heating issatisfactory. After operating under `total reux conditions untilequilibrium is obtained, the condenser is .then moved to a positionwhere the inner end is above horizontal. In this position the condensatetlows along the condenser and subsequently into the receiver.

The still is normally operated under vacuum, and the evacuat-ing portshould be large enough to prevent a back pressure build up from the highrate of evacua-tion caused by the large lm area. The position of thecondenser inside the vaporizing chamber aids in preventing vaporpressure build up, and hence, the pressure inside the vaporizing chamberis substantially the same as in the casing. The lack of packing gl-ands,also, greatly aids in maintaining the desired vacuum, so that only asmall pump is required to remove the non-condensable gases.

The construction of the still makes a very short path vapor ow from theevaporating surface to the condensing surface. The vapor path is,furthermore, a straight line unobstructed flow, increasing eiiciency anddecreasing both back pressure and vapor hold up.

In the embodiment illustrated, the still is for batch 0peration.However, by adding a feed tube and a residue withdrawal tube into thevaporizing chamber, the still f will operate continuously.

Others may readily adapt the invention for use under various conditionsof service, by employing one or more of the novel features disclosed orequivalents thereof. As at present advised with respect to the apparentscope of our invention, we desire to claim the following subject matter.

We claim:

1. Vacuum distillation apparatus comprising, a cylinder, evacuatingmeans for said cylinder, closure means abutting one end of saidcylinder, a vaporizing chamber axially disposed in said cylinder,condenser means closing the other end of said cylinder and extendinginto said chamber, the inner end of said condenser being movable withrespect to the axis of the vaporizing chamber, said chamber rotatablyconnected to said closure means, means for rotating said chamber, andradiant heating means externally disposed on said cylinder.

2. Vacuum distillation apparatus, comprising, a cylinder having a fulldiameter opening at one end thereof, -a vaporizing chamber axiallydisposed in said cylinder, an imperforate bearing casing closing saidfull diameter opening, condenser means closing the other end of saidcylinder and extending into said chamber, the inner end of saidcondenser being movable with respect to the axis of the vaporizingchamber whereby the rate of collecting the distillate is variable meansfor evacuating said cylinder, distillate receiving means communicatingwith said condenser, said chamber having one end wall with an axialprojection thereon and a partial end wall at the other end thereof,bearing means in said casing rotatably holding said chamber, means forrotating said chamber, :tilnd external radiant heating means supplyingvaporizing eat.

3. Vacuum distilla-tion apparatus comprising, a cylinder having a fulldiameter opening, evacuating means for said cylinder, an axiallydisposed cyl-indrical distillation chamber in said cylinder, animperfor-ate bearing casing closing said open end of said cylinder,movable condenser means closing the other end of said cylinder andpartially extending into said chamber, a distillate receivercommunicating with said condenser, said chamber having an end wall and aprojection thereon, a bearing disposed in said casing, a chuck mountedon said bearchamber in rotatable position in said cylinder, means 1n thenature of a pair of magnets for rotating said chamber, one of saidmagnets disposed externally of said casing yand attached to a drivemotor, the other said magnet internally disposed in said casing andattached to said chuck, the inner end of said condenser movable abovehorizontal for collecting distillate and below horizontal for totalreux, and external radiant heating means for supplying heat to saidchamber.

4. Vacuum distillation apparatus comprising, a generally horizontallydisposed cylinder having one full diametcr open end, a concentricdistillate chamber having one partially open end rotatably mounted insaid cylinder,

imperforate closure means sealing said full diameter open 15 ing,movable condenser means closing the other end of said cylinder andextending into said cylinder, evacuating means for said cylinder,receiver means communicating with said condenser, means for rotatingsaid chamber, and

external means for supplying vaporizing heat, said condenser adapted tobe moved with the internal end below Ihorizont-al position for totalreflux and above horizontal position for distillation.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 10 2,129,596 Waterman et al Sept, 6, 1938 2,526,676 Lovet-tOct. 24, 1950 2,538,967 Hickman Jan. 23, 1951 2,554,703 Hickman May 29,1951 FOREIGN PATENTS Number Country Date 718,347 Germany Mar. 10, 1942614,388 Great Britain Dec. 15, 1948

1. VACUUM DISTILLATION APPARATUS COMPRISING, A CYLINDER, EVACUATINGMEANS FOR SAID CYLINDER, CLOSURE MEANS ABUTTING ONE END OF SAIDCYLINDER, A VAPORIZING CHAMBER AXIALLY DISPOSED IN SAID CYLINDER,CONDENSER MEANS CLOSING THE OTHER END OF SAID CYLINDER AND EXTENDINGINTO SAID CHAMBER, THE INNER END OF SAID CONDENSER BEING MOVABLE WITHRESPECT TO THE AXIS OF THE VAPORIZING CHAMBER, SAID CHAMBER ROTATABLYCONNECTED TO SAID CLOSURE MEANS, MEANS FOR ROTATING SAID CHAMBER, ANDRADIANT HEATING MEANS EXTERNALLY DISPOSED ON SAID CYLINDER.